PL
ENOCR — text recognition
Characters sit in a single line, one after another. A letter means the same thing wherever it appears on the page.
Optical Music Recognition
OMR: optical music recognition explained
OMR is technology that reads music notation from an image — a scan, a photo or a PDF — and turns it into data you can work with: a MIDI file, a MusicXML score or practice recordings for each voice part. Below we explain how it works, what it is useful for and where its limits are.
PDF · photo · scanMIDI · MusicXML · recordings
What is OMR?
OMR stands for Optical Music Recognition. The software takes an image of a page of sheet music and returns notation a computer can understand: which pitches, in what rhythm, in which voice and with which words.
For a musician this is simply reading music. For a computer a scan is just a grid of dots of varying brightness — it does not know that a black blob on the third line is a notehead and the vertical line next to it is its stem. OMR teaches it to tell them apart.
Music recognition is useful wherever sheet music exists only on paper or as a scanned PDF, and you need a digital version: to listen to it, edit it, transpose it or prepare recordings for your ensemble.
OMR vs OCR
OMR — music recognition
Notation is two-dimensional: pitch is vertical position, time runs horizontally, and several voices sound at once. What a note means depends on the clef, the key signature and what happened earlier in the bar.
How music recognition works
Put simply, the software follows the same path as a musician reading a new score — from an image of the page to music that can be heard.
Image preparation
The page is straightened and cleaned up so that the notation is as legible as possible.
Symbol recognition
The software finds the staves and the notation symbols: notes, rests, clefs, accidentals. Today this is usually done with machine learning.
Reading the music
The symbols become music: pitches, rhythm, voice parts and the lyrics under the notes.
Saving the result
The finished score is saved as MusicXML and MIDI files — for editing, listening or preparing recordings.
What you can use OMR for
Once recognised, sheet music stops being a picture and becomes material you can actually work with.
Practice recordings
Each voice part on its own, at any tempo. A singer who does not read music fluently learns their line at home instead of meeting it for the first time at rehearsal.
Editing in notation software
Open the MusicXML file in MuseScore, Sibelius, Dorico or Finale. Fix errors in an old edition, add performance markings, prepare a clean print.
Transposition
Move a piece that sits too high for your ensemble into a more comfortable key with a single command, without rewriting every part by hand.
Digitising an archive
Old songbooks, out-of-print editions and worn photocopies stop being the only copy. Digital notation is easy to duplicate, search and print again.
Extracting parts
Pull individual parts out of a full score — for a choir section or for instrumentalists who play a single line.
Accessibility
Digital notation can be printed in large format, and a MusicXML file can also be converted into braille music for blind and partially sighted musicians.
MIDI or MusicXML — what you actually get
Recognition results are usually saved in two formats. They look similar because both contain notes, but they serve different purposes.
| Feature | MIDI | MusicXML |
|---|---|---|
| What it stores | Sound: the pitch, start and length of each note | Notation: notes, rests, clefs, time and key signatures |
| Lyrics | Usually ignored by software | Kept — each syllable attached to its note |
| Score layout | Not stored — notation software has to guess it | Kept: bars, voices, slurs, dynamics |
| Best for | Listening, learning parts, working in a recording app | Editing, printing and transposing in notation software |
| Opens in | MIDI players, recording apps, notation software | MuseScore, Sibelius, Dorico, Finale and other notation software |
In short: MIDI tells you how a piece sounds, MusicXML how it is written. If you plan to correct the notes, start from MusicXML.
Where OMR goes wrong
Music recognition is not error-free, and it is fairer to say so up front. The most common trouble spots are:
- Handwritten scores
- Handwriting is much harder for software than print. OMR systems work best with printed music.
- Poor image quality
- Blurry photos, shadows, folded pages or copies of copies.
- Dense or unusual notation
- Elaborate scores and unconventional notation usually need more corrections.
- Lyrics
- Several verses or several languages under one line of music.
That is why a recognition result is worth checking before it reaches the ensemble.
How to prepare sheet music for recognition
The quality of the result depends largely on the quality of the image. A few simple rules make a big difference.
- If you have a PDF exported straight from notation software, use it instead of scanning a printout — it is the best material you can give.
- Scan at 300 dpi. That is usually enough, and higher resolutions rarely improve the result.
- Keep the page flat and straight, with the whole page — margins included — in the frame.
- Take photos in even light, without the shadow of your hand or phone and without flash glare.
- A black-and-white or greyscale scan reads better than a colour photo of yellowed paper.
In testing
OMR in ReChoir: from a PDF to recordings for the ensemble
In ReChoir, music recognition is not a separate program but part of the ensemble's repertoire. The conductor uploads a score, and the singers get practice material in their digital folder.
Built for choral scores
Several voices, systems joined by a brace, lyrics under the notes — not an exception, but the basic case.
Part recordings
Each voice part on its own, played on an instrument, plus all voices together.
Files for further work
MIDI and MusicXML to download if you want to refine the score in your own notation software.
Lyrics in your language
When uploading, you choose the language of the words — including Polish, Latin, German and English.
The feature is in testing — first with invited ensembles, and now with anyone who would like to try it on their own music.
Test version · free
Try it on your own sheet music
We have opened our tester to everyone — no choir account, no asking for permission. You upload a PDF, sign in with Google, and a moment later you get the recognised score back: MIDI and MusicXML files plus recordings to listen to. It costs you nothing.
Honestly: this is not the final accuracy yet
We are at an early stage — the program reads more and more, but we are still refining it and it does make mistakes. It may drop a dot that lengthens a note, attach a sharp or a flat to the neighbouring notehead, or miss one voice where two share a staff. Dense, unusual or poorly scanned notation gives it the hardest time. If something comes out wrong, it is not your fault and really no reason to give up on it: those are exactly the cases we value most, because that is how we teach the program. Treat the result as a preview of what is coming — and tell us what did not work.
What the test version includes
- Three PDF files per person — usually enough to form an opinion.
- The first three pages of each file — more than enough to see how the program handles your music.
- No fees and no commitments — we ask for nothing beyond signing in with Google.
The limits come from simple arithmetic: recognising a single page takes a fair amount of work from our servers, and testers are arriving faster than we expected. We would rather let more people in with a smaller allowance than a handful with none.
Try it for free
Running an ensemble and need more than a few trial pages? Get in touch — we would be glad to talk about your choir's music.
Frequently asked questions about OMR
What is the difference between OMR and OCR?
OCR recognises text, OMR recognises music. Text is read in a single line, and a letter's meaning does not depend on where it sits. In music, vertical position (pitch) and horizontal position (time) both matter, as do the clef, the key signature and what happened earlier in the bar. That makes OMR a considerably harder task than OCR — although it uses OCR as one of its stages when reading lyrics.
Does OMR work with a photo taken on a phone?
Yes, provided the photo is sharp, taken straight above the page and in even light. In ReChoir you upload it as a PDF — which is how document scanning apps save photos. A scan or a PDF exported from notation software usually gives a better result, though.
Can OMR read handwritten music?
Handwritten scores are much harder for OMR than print, because everyone writes music differently. Recognition in ReChoir is built primarily for printed music — with a manuscript the result may need a lot of corrections.
Is music recognition error-free?
No. Even with a good scan, mistakes happen — most often with poor image quality, dense notation and in the lyrics. It is worth checking the result before it reaches the ensemble.
Does OMR read the lyrics under the notes?
Yes, although it is a separate task: the words have to be read first and then assigned to the right notes, taking melismas into account. In ReChoir, specifying the language of the lyrics when uploading helps with this.
How do I open recognised music in MuseScore, Sibelius or Dorico?
Use the MusicXML file — it is the exchange format between notation programs. In most of them you simply choose “Open” or “Import” and select the file. A MIDI file will open too, but the program then has to guess the notation, so the result tends to be less readable.
Can recognised music be turned into recordings for a choir?
Yes. A MIDI file contains all the voices, so each of them can be played back separately. In ReChoir, part recordings are created automatically after recognition and added to the ensemble's repertoire.
Can I recognise any sheet music?
Technically yes, but recognition does not change the rights to the work or the edition. You use the digital notation on the same terms as a copy of the sheet music — if the work or edition is protected, the same restrictions apply.
When will OMR be available in ReChoir?
The feature is already running with our first test ensembles. If you would like your choir to join them, get in touch using the form below.
Contact
Would you like to bring ReChoir to your ensemble, or simply talk it through? Leave us a message — we'll get back to you.
